Taylor Jordan A, Thoroughman Kurt A
Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO 63130, USA.
J Neurophysiol. 2007 Jul;98(1):317-26. doi: 10.1152/jn.01070.2006. Epub 2007 Apr 25.
When humans experience externally induced errors in a movement, the motor system's feedback control compensates for those errors within the movement. The motor system's predictive control then uses information about those errors to inform future movements. The role of attention in these two distinct motor processes is unclear. Previous experiments have revealed a role for attention in motor learning over the course of many movements; however, these experimental paradigms do not determine how attention influences within-movement feedback control versus across-movement adaptation. Here we develop a dual-task paradigm, consisting of movement and audio tasks, which can differentiate and expose attention's role in these two processes of motor control. Over the course of several days, subjects performed horizontal reaching movements, with and without the audio task; movements were occasionally subjected to transient force perturbations. On movements with a force perturbation, subjects compensated for the force-induced movement errors, and on movements immediately after the force perturbation subjects exhibited adaptation. On every movement trial, subjects performed a two-tone frequency-discrimination task. The temporal specificity of the frequency-discrimination task allowed us to divide attention within and across movements. We find that divided attention did not impair the within-movement feedback control of the arm, but did reduce subsequent movement adaptation. We suggest that the secondary task interfered with the encoding and transformation of errors into changes in predictive control.
当人类在运动中经历外部诱发的错误时，运动系统的反馈控制会在运动过程中补偿这些错误。然后，运动系统的预测控制会利用有关这些错误的信息来指导未来的运动。注意力在这两个不同的运动过程中的作用尚不清楚。先前的实验揭示了注意力在许多运动过程中的运动学习中的作用；然而，这些实验范式并未确定注意力如何影响运动中的反馈控制与跨运动适应。在这里，我们开发了一种双任务范式，由运动任务和音频任务组成，它可以区分并揭示注意力在这两个运动控制过程中的作用。在几天的时间里，受试者进行水平伸展运动，有音频任务和无音频任务；运动偶尔会受到瞬态力扰动。在受到力扰动的运动中，受试者补偿了力引起的运动误差，并且在力扰动后的立即运动中受试者表现出适应性。在每次运动试验中，受试者执行一个双音频率辨别任务。频率辨别任务的时间特异性使我们能够在运动内和运动间分配注意力。我们发现，注意力分散不会损害手臂在运动中的反馈控制，但会减少随后的运动适应性。我们认为，次要任务干扰了错误的编码以及将错误转化为预测控制变化的过程。
